A chapter or so from now would be a really good time for someone to bring up The Demon King's Prophecy from, like, 400 chapters ago, and how thoroughly Iruma fits it. Would make a strong catalyst for a "prove you can hang" deal to take shape.
Especially since Iruma is already in the running for...
Tbh that would've unironically been a great plan had she been alone in there like the cultist seemed to think she would be. Only thing better than an "inescapable trap" is an "inescapable trap" that tricks the target into wasting their energy trying to do stuff that won't make the trap escapable.
They were canonically on ice at that point, IIRC. As in, they fucked up so badly that they all fled to Antarctica and conveniently missed like half of the 20th Century.